What version of VP are you using? This is the latest. For licensed users upgrades are free for up to six months. After that, VP will continue to fully function but a fee will be required in order to register the newest.
When you refer to "three boxes" do you mean the video effect aspect ratio choices?
In the export window don't simply accept the suggested resolution. Click the chevron to the right of that box and manually choose it - perhaps 1920 x 1080P.
The only way others can sleuth the issue is if you share the project, not the export. Here's how ... http://nch.invisionzone.com/topic/23659-tips-for-getting-help-on-this-forum/